Process manufacturing companies, chemical companies, food industries, water treatment facilities, and the like are, on a daily basis, taking the safety of their employees more and more seriously and, accordingly, are continually looking for ways to improve their safety records by minimizing the number of injuries at their work place. Employee safety is further encouraged by the Occupational Safety and Health Administration (OSHA) which requires that companies insure that their employees have a safe working environment, and that companies develop policies and procedures for maintaining operating equipment.
In view of the foregoing, most manufacturing facilities have developed procedures referred to as “lock-out” and “tag-out” procedures for employees to implement whenever a piece of equipment needs to be isolated or brought down for maintenance. In most cases, such procedures require that valves and electric motors be locked, de-energized, or fixed so they are inoperable. Most valves have actuators mounted on them to allow computers and other programmable logic controllers (PLCs) to open and close such valves. There are, however, a number of shortcomings with such procedures. For example, some procedures require devices that are prohibitively expensive, or such devices failed to do what they were supposed to do, or they were simply too difficult and/or time-consuming to install or make work. Such devices, when not being used, also require storage space and some means of tracking the devices.
In other cases, rather than using devices to lock-out valves, the air supply to the respective actuators that control the valves is removed in an attempt to prevent the valves from opening during preventive maintenance or a major shutdown. A drawback with this method is that the valves controlled by actuators are valves, such as butterfly valves, which open or close with a turn of about 90°. When pressure builds up or is exerted against the valve seat of such valves; the valve will tend to open, if only slightly, but even if only slightly, fluid that leaks by such a valve could render a work area, such as the interior of a vessel, hazardous.
Accordingly, a continuing search has been directed to the development of a simpler and more secure way to lock-out and secure an actuator and valve so that the valve cannot leak fluid when closed, and thereby maintain safety for men working and/or repairing equipment.